Breakaway structure for body implantable medical device

Abstract

A cardiac lead is provided that includes a connector for connecting to a cardiac stimulator and a flexible sleeve coupled to the connector. The sleeve has a first segment, a second segment and a jacket coupling the first segment and the second segment. The jacket is composed of a shape-memory polymeric material which deforms diametrically in situ to selectively disconnect the first segment from the second segment. An electrode is coupled to the sleeve and a conductor is disposed in the sleeve and coupled to the connector and the electrode for conveying electrical signals. The breakaway function of the jacket allows removal of all but a small portion of the lead without dissection of fibrous tissue.

What is claimed is: 
     
       1. A cardiac lead, comprising: a connector for coupling to a cardiac stimulator;   a flexible sleeve coupled to the connector and having a first lumen;   a clamp coupled to the flexible sleeve and being composed of a shape-memory polymeric material;   a tine coupled to the clamp and having an end projecting away from the flexible sleeve whereby the clamp may be selectively deformed diametrically in situ to disconnect the tine from the clamp;   an electrode coupled to the sleeve; and   a conductor wire coupled to the connector and to the electrode for conveying electrical signals.   
     
     
       2. The cardiac lead of claim 1, comprising a second electrode coupled to the sleeve and a second conductor coupled to the second electrode and the connector. 
     
     
       3. The cardiac lead of claim 1, wherein the clamp has a second lumen in fluid communication with the first lumen to enable fluid to flow into the clamp. 
     
     
       4. The cardiac lead of claim 1, wherein the clamp comprises a cylindrical member, the tine being disposed in the cylindrical member, and the cylindrical member expands diametrically in situ.